In recent years, research and development has flourished on biometric authentication technology that uses physical characteristics of an individual in place of codes and passwords made by combining characters and numbers. In biometric authentication, physical characteristics that differ between individuals are typically used, such as fingerprints, the vein pattern on the back of the hand, the iris pattern of an eye, the voiceprint or the like. In particular, biometric authentication using fingerprints or the vein pattern on the back of the hand have begun to be installed in various systems such as ATMs (Automatic Teller Machines) and personal computers (PCs) as authentication precision has increased and device costs have come down.
However, authentication using fingerprints or the vein pattern on the back of the hand requires the target individual to make part of the body such as the fingers or the hand come into contact with or become close to a certain degree to the apparatus. Consequently, biometric authentication technology using the iris pattern of an eye has attracted attention recently. (For example, see Patent Literature 1).